fix: move LayoutStudio before per-audio section and add ultrafast preset + 1fps output

- LayoutStudio was buried after the per-audio list, making settings invisible
  before submit; moved it right after the Files section so layout/watermark
  settings are always visible in the workflow
- Add -preset ultrafast and -r 1 to both libx264 encode paths; without a
  preset FFmpeg defaults to medium and wastes time on motion estimation for
  still images; -r 1 avoids 25x frame synthesis overhead on 1080p

lib/ffmpeg/encode.ts

@@ -283,8 +283,12 @@ export async function encodeVideo(options: {
     args.push(
       "-c:v",
       "libx264",
+      "-preset",
+      "ultrafast",
       "-tune",
       "stillimage",
+      "-r",
+      "1",
     );
     pushAudioEncodeArgs(args, audioEncode);
     args.push(
@@ -382,8 +386,12 @@ export async function encodeVideo(options: {
   args.push(
     "-c:v",
     "libx264",
+    "-preset",
+    "ultrafast",
     "-tune",
     "stillimage",
+    "-r",
+    "1",
   );
   pushAudioEncodeArgs(args, audioEncode);
   args.push(